Syntheses, X-ray structures and properties of a dinuclear cadmium(II)azido and a polymeric cadmium(II)thiocyanato compounds containing bis(tridentate) congregators

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• 作者：Habibar Chowdhury ; Rajarshi Ghosh ; Sk. Hafijur Rahaman ; Barindra Kumar Ghosh
• 关键词：Cadmium(II) azide/thiocyanate ; Bis(tridentate) Schiff base ; Superstructure ; Luminescence
• 刊名：Polyhedron
• 出版年：2007
• 出版时间：30 October 2007
• 年：2007
• 卷：26
• 期：17
• 页码：5023-5029
• 全文大小：870 K

文摘

One-pot reactions of cadmium(II) perchlorate/nitrate, Schiff bases (pbap/pfap) and pseudohalides (sodium azide/ammonium thiocyanate) in a 2:1:4 molar ratio in MeOH–MeCN solvent mixtures at room temperature result in a dinuclear compound [Cd₂(pbap)(OH₂)₂(N₃)₄] (1) [pbap = N-(1-pyridin-2-ylbenzylidene)-N-[2-(4-{2-[(1-pyridin-2-ylbenzylidene)amino]ethyl}piperazin-1-yl)ethyl]amine] and a polymeric compound [Cd₂(pfap)(μ_1,3-NCS)(μ_1,3-SCN)(NCS)₂]_n (2) [pfap = N-(1-pyridin-2-ylformylidene)-N-[2-(4-{2-[(1-pyridin-2ylformylidene)amino]ethyl}piperazin-1-yl)ethyl]-amine]. X-ray crystal structural analyses reveal a bis(tridentate) congregation behaviour of the hexadentate blocker (pbap/pfap) encapsulating two metal centers. Each cadmium(II) center in 1 and 2 is in a distorted octahedral geometry with CdN₅O and CdN₅S chromophores, respectively. In 1, the dinuclear units participate in intermolecular O–HN hydrogen bonding between bound water O atoms and terminal azide N atoms, in combination with C–Hπ interactions, resulting in a 3D supramolecular network with an intramolecular CdCd distance of 6.473(2) Å. In the crystal lattice, the covalent 1D chain of 2 is further engaged in face-to-face ππ interactions from two terminal pyridine rings, which stabilizes the chain with an intradimer CdCd separation of 6.640(5) Å. Both the complexes display intraligand ¹(π–π^*) fluorescence and intraligand ³(π–π^*) phosphorescence in glassy solutions.